diff --git a/lib/types/filter-types.js b/lib/types/filter-types.js
--- a/lib/types/filter-types.js
+++ b/lib/types/filter-types.js
@@ -10,6 +10,9 @@
   typeof calendarThreadFilterTypes,
 >;
 
+export type CalendarCommunityFilter = {
+  +threadIDs: $ReadOnlyArray<string>,
+};
 export type CalendarThreadFilter = {
   +type: 'threads',
   +threadIDs: $ReadOnlyArray<string>,
@@ -23,6 +26,8 @@
 export const updateCalendarThreadFilter = 'UPDATE_CALENDAR_THREAD_FILTER';
 export const clearCalendarThreadFilter = 'CLEAR_CALENDAR_THREAD_FILTER';
 export const setCalendarDeletedFilter = 'SET_CALENDAR_DELETED_FILTER';
+export const updateCalendarCommunityFilter = 'UPDATE_CALENDAR_COMMUNITY_FILTER';
+export const clearCalendarCommunityFilter = 'CLEAR_CALENDAR_COMMUNITY_FILTER';
 
 export type SetCalendarDeletedFilterPayload = {
   +includeDeleted: boolean,
diff --git a/lib/types/redux-types.js b/lib/types/redux-types.js
--- a/lib/types/redux-types.js
+++ b/lib/types/redux-types.js
@@ -30,6 +30,7 @@
   CalendarFilter,
   CalendarThreadFilter,
   SetCalendarDeletedFilterPayload,
+  CalendarCommunityFilter,
 } from './filter-types';
 import type { LifecycleState } from './lifecycle-state-types';
 import type { LoadingStatus, LoadingInfo } from './loading-types';
@@ -679,6 +680,14 @@
       +type: 'SET_CALENDAR_DELETED_FILTER',
       +payload: SetCalendarDeletedFilterPayload,
     }
+  | {
+      +type: 'UPDATE_CALENDAR_COMMUNITY_FILTER',
+      +payload: CalendarCommunityFilter,
+    }
+  | {
+      +type: 'CLEAR_CALENDAR_COMMUNITY_FILTER',
+      +payload: void,
+    }
   | {
       +type: 'UPDATE_SUBSCRIPTION_STARTED',
       +payload?: void,
diff --git a/web/redux/redux-setup.js b/web/redux/redux-setup.js
--- a/web/redux/redux-setup.js
+++ b/web/redux/redux-setup.js
@@ -15,7 +15,10 @@
 import type { DraftStore } from 'lib/types/draft-types';
 import type { EnabledApps } from 'lib/types/enabled-apps';
 import type { EntryStore } from 'lib/types/entry-types';
-import type { CalendarFilter } from 'lib/types/filter-types';
+import type {
+  CalendarFilter,
+  CalendarCommunityFilter,
+} from 'lib/types/filter-types';
 import type { LifecycleState } from 'lib/types/lifecycle-state-types';
 import type { LoadingStatus } from 'lib/types/loading-types';
 import type { MessageStore } from 'lib/types/message-types';
@@ -57,6 +60,7 @@
   updatesCurrentAsOf: number,
   loadingStatuses: { [key: string]: { [idx: number]: LoadingStatus } },
   calendarFilters: $ReadOnlyArray<CalendarFilter>,
+  communityFilter: ?CalendarCommunityFilter,
   urlPrefix: string,
   windowDimensions: WindowDimensions,
   cookie?: void,